Y-chromosome Haplogroup I2a2

 

A couple of months ago, my wife and I decided to participate in the Genographic Project run by National Geographic and IBM. We ordered 3 kits at about $100 each from their web site. A month later, we got our kits, including welcome materials and DNA sampling materials. We swabbed the insides of our cheeks and sent the vials back in the prepaid envelopes. A few weeks later the lab was finished and our results were ready to access online. This is where to start if you want to participate in The Genographic Project.

Each Genographic Project kit analyzes either your mitochondrial DNA (MtDNA) or your Y-chromosome DNA. A basic understanding of mitochondrial DNA and of chromosomes is needed to make sense of the results.

MtDNA: matrilineal haplogroup

I am MtDNA haplogroup K. That means my mitochondrial DNA differs from the Cambridge Reference Sequence mitochondrial DNA at base pairs 16224C, 16311C, and 16519C in what is called Hyper Variable Region 1 (HVR1): those are the defining mutations for haplogroup K. Those mutations are relatively rare, shared by only about 8% of Europeans. Haplogroup K is also called Clan Katrine, the name retroactively given the first woman whose MtDNA had those defining mutations by Bryan Sykes in his 2001 book, The Seven Daughters of Eve. Clan Katrine includes other famous people, including Stephen Colbert, Katie Couric, and Otzi the Iceman, a 5,000 year-old mummy found in the Alps. Further testing by FamilyTreeDNA located additional mutations at 146C and 152C in HVR2, the defining mutations for haplotype 2a of haplogroup K, making my MtDNA haplogroup K2a, a relatively rare haplotype within haplogroup K. That is only the beginning of the story, however: this piece of information about my mitochondrial DNA opens out to a panoramic view of my matrilineal descent.

I am MtDNA haplogroup K2a and Y chromosome haplogroup I2a2. That statement offers a panoramic view of my ancestral past, but it sits atop a mountain of understanding.

I am Y chromosome haplogroup I2a2. That means the 12 locations on my Y chromosome which were analyzed for their short tandem repeats (STRs) fit a particular genetic pattern which places me in Y chromosome haplogroup I. I have a particular mutation called marker P37.2 that places me in subclade I2a2 Researchers call that particular haplotype I2a2 Dinaric, named after the Dinaric Alps region of the South Slavic Balkans which have the highest concentration of this genetic pattern. This, too, only begins the story, however: this piece of information about my Y chromosome DNA opens out to vast vistas across time and space.

My deep genetic past

Scientists, using DNA evidence, put the emergence of Homo sapiens sapiens at about 200,000 years ago. The oldest bones of our species that we have found have been dated to about 130,000 years ago. A very important member of our species has been termed “Mitochondrial Eve”. This woman lived from about 150,000 to 170,000 years ago. She is special not because she was the first woman: there were many other women alive at the time she was. Mitochondrial Eve was important because her mitochondrial DNA has been passed down, in matrilineal descent, to every single person alive today: she is our common mother. Eve lived in East Africa.

The mitochondrial DNA of the daughters of Eve mutated after a number of generations into 2 different forms, termed L0 and L1. The concentration of the L0 and L1 variants of mitochondrial DNA is, to this day, highest in East Africa. After thousands of years, a variant of L1 DNA emerged. Today, L2 mitochondrial DNA is most concentrated in West Africa. About 80,000 years ago, a woman with L2 mitochondrial DNA gave birth to a girl with mutations which would develop into a new haplogroup, L3. Persons with L3 MtDNA are found all over Africa, but they are in high concentrations in Northern Africa. Members of haplogroup L3 moved north through the Middle East and were the first humans to leave Africa, probably around the time of the African Ice Age 60,000 years ago.

My MtDNA past so far is: MtDNA Eve (160,000)–> L1 –> L2 –> L3 (80,000)

The African Ice Age of about 60,000 years ago is where my patrilineal descent begins. A male with Y-chromosome marker M168 lived about 50,000 years ago in northeast Africa and his Y-chromosome DNA is in every non-African man living today: his was the only lineage to survive outside of Africa.

About 45,000 years ago, there was a mutation in the Y-chromosome in the M168 line: the M89 marker is found in 90-95% of all non-African males. The first man with marker M89 was born in Northern Africa or the Middle East.

The story of my Y-chromosome DNA thus far is: M168 (50,000) –> M89 (45,000)

On the female side of things, about the time that M89 emerged, a woman with L3 MtDNA had a baby girl who gave rise to a new haplogroup, termed N. Her descendents lived in the Eastern Mediterranean and Western Asia. After a few thousand years of exploration and settlement, the descendents of the founding member of haplogroup N, gave rise to a woman with a new mutation. This woman gave rise to haplogroup R. Some of the members of haplogroup R migrated north across Turkey and into the Caucasus mountains of Georgia and Russia.

About 50,000 years ago, a woman in MtDNA haplogroup R gave birth to a girl with a set of mutations which are considered to be determinative of a new haplogroup, U. This founding mother of haplogroup U has been given the name Ursula. Clan Ursula, as it is now called, spread throughout Europe and settled into isolated refuges as the Ice sheets descended from the north in the last Glacial Maximum.

Thus far, the matrilineal descent looks like this:

MtDNA Eve (160,000)–> L1 –> L2 –> L3 (80,000)–> N (60,000)–> R –> U (50,000)

On the male side of things, about 20,000 years ago, in an isolated refuge from the last Glacial Maximum, the last great Ice Age, somewhere in the Balkans, a man with Y-chromosome DNA M89 gave birth to a son with mutations which would come to define haplogroup I. Those mutations are defined by marker M170.

As the ice sheets of the Last Glacial Maximum began to retreat in Europe, many of the descendants of haplogroup I followed northward. My descendants probably did not. About 15,000 years ago, a boy was born to a haplogroup I male with Y-chromosome mutations which defined haplotype I1b. This mutation is determined by marker P37.2 on my Y-chromosome. This man lived in central and southeastern Europe, likely in an Ice Age refuge in the Adriatic region of modern-day Croatia. As far as our personal ancestry goes back, my patrilineal ancestry is confined to the same small geographical area in the Dinaric Alps of the South Slavic Balkans. The men of my past are homeboys of the first order: they seem to have lived in the same neighborhood in every generation for about 20,000 years back. No wonder moving has always stressed me out so much!

My complete Y-chromosome deep ancestry looks like this:

M168 (50,000) -> M89 (45,000) -> I (M170 20,000)-> I2 (P37.2 15,000)

Back to the women. About 16,000 years ago, Katrine, the founding mother of MtDNA haplogroup K was born, probably in southern Russia or the steppes of the Black Sea. Katrine was a descendant of a woman in Clan Ursula, specifically in subclade U8. The most likely explanation has Katrine being born in a haplogroup U8 tribe moving north in Europe, following the retreating ice sheets as the last Glacial Maximum retreated north. My specific haplotype, K2a, emerged from haplogroup K in the last few thousand years in Europe and my mother passed that mitochondrial DNA down to me.

My complete MtDNA deep ancestry looks like this:

Eve (160,000)-> L1-> L2-> L3 (80,000)-> N (60,000)-> R-> U (50,000)-> K (16,000)

I am MtDNA haplogroup K2a and Y chromosome haplogroup I2a2. That statement offers a panoramic view of my ancestral past, but it sits atop a mountain of understanding.

 Posted by on June 28, 2010

  2 Responses to “Y-chromosome Haplogroup I2a2”

  1. Thank you for the clearest explanation I have heard so far. (Dr. Ken Nordtvedt (sp?) talks over my head, but I don;t fault him, I lack the science background). My husband and son are I2a2, and I found this site by googling at length. Hubby’s dad did come here from Croatia, so homeboy fits his line, too! (Only a bit of travel was indicated, as at the rise of surnames our name may have started out Hessian, but we got it via Hungary–some sort of boomerang effect from leaving the genetic homeland?)

  2. Hi Mike-this is uncle Andy…
    I watch the development in amazement…That is one beautiful baby.You and Jessica make not only Your grandparents proud but also families on both sides – me and Mira and Your cousins
    We all love you guys,uncle Andy